Hydrapulse motor



H." R. LINDERFELT Oct. 22, 1-963 HYDRAPULSE MOTOR 4 Sheets-Sheet 1 Filed Nov. 16, 1959 BY 270401 V ATTORNEYS Oct. 22, 1963 H. R. LINDERFELT 3,107,486

HYDRAPULSE MOTOR Filed Nov; 16, 1959 4 Sheets-Sheet 2 1H 01. .RQL/NDERFEL T IN VENTOR BY p M ATTO'RN EYs Oct. 22, 1963 H. R. LINDERFELT 3,107,486

HYDRAPULSE: MOTOR 4 Sheets-Sheet 3 Filed Nov. 16, 1959 11191.. R.L/NDERFEL7' INVENTOR BY aw ATTCRNEYS Oct. 22, 1963 LINDERFELTY 3,107,486

HYDRAPULSE MOTOR Filed Nov. 16, 1959 4 Sheets-Sheet 4 IZI INVENTO BY Wm wk/M ATTOR N EY 5 04 12 L/NDERFEL 7' United States Patent 3,107,486 HYDRAPULSE MUTGR Hal R. Lindcrfelt, Tarzana, Calif. (9772 Rangevievv Drive, Santa Ana, Calif.) Filed Nov. 16, 1959, Ser. No. 853,174 4 Claims. (Cl. 6tl35.6)

This invention has to do with propulsion motors of the type wherein products of combustion of a pulsing type internal combustion engine are exhausted into a liquid medium for the purpose of pumping the medium or propelling an object in the medium by reaction. A motor of this type is shown in the co-pending application of Neils I. Beck, Joseph E. Leach, In, and Hal R. Linderfelt for Pulse Jet Propulsion Device and Method of Operating Same, Serial No. 597,998, now Patent No. 3,024,597.

The thrust obtainable from a motor of the type under consideration is proportional to the amount of liquid that can be pumped through the propulsor or propulsion unit thereof per unit of time. The amount of liquid pumped is a function of the cycling speed and this in turn depends, up to a practical maximum, upon the rate at which the propulsor can be filled with liquid. Therefore, a primary object of the invention is to provide a novel and improved pulse jet liquid propulsion device particularly designed to increase the cycling rate of the motor by decreasing the time required to fill the propulsor.

There are several factors which affect the filling rate of the propulsor. One of these is the inertia of the liquid, as for example, if this is water, it is some 774 times as heavy as air. Consequently, to accelerate or decelerate it rapidly requires considerable power. An object of the invention is to provide a propuisor which is so constructed and designed as to avoid rapid accelerations and decelerations of the liquid medium by providing for a secondary liquid flow through the propulsor itself alongside the chambers to be filled cyclically with liquid.

Another factor affecting the filling rate of the propulsor device is the inlet area available and a further object of the invention is to provide a novel construction embodying a plurality of valved ejector chambers having a relatively large inlet valve area for each unit of interior space which must be filled and to provide novel valves which afford minimum resistance to the entry of liquid.

A further factor which affects the filling rate of the propulsor is the pressure differential between the space to be filled and the space exterior thereto. Another object of the invention is to provide means for controlling flow of fluid externally of the chambers to be filled in a manner to increase the pressure differential between the fluids in the space to be filled and the space immediately surrounding the same.

The filling rate of the propulsor is also affected by the sponge volume of gas by which is meant the volume of exhaust gas which is residual in the conduit connecting the combustion chamber and the p-ropulsor unit. This gas must be compressed at each explosion and expanded at each exhaust portion of the cycle, and therefore must be jettisoned through the propulsor before liquid can start to fill the propulsor. Consequently, another object of the invention is to provide means for reducing the sponge volume of gas to a minimum.

The filling rate of the pro-pulsor is also affected by obstruction to the flow of residual exhaust gas through the entering liquid and therefore a further object of the invention is to provide in a propulsor, novel ejector chambers or cavities which are designed to facilitate the ejection of the gas therefrom.

A final major factor affecting the filling rate of the propulsor is the distance which must be travelled by the liquid in filling the ejector chambers of the propulsor. A further object is to provide a contsruction wherein the ice distance which must he travelled by the liquid to fill the ejector has been reduced to a minimum.

These and other objects will be apparent from the drawings and the following description. Referring to the drawings, which are merely for illustrative purposes:

FIG. 1 is an elevational View of a hydrapulse motor embodying the invention shown attached to the rear or transom of a boat and showing certain of the apparatus in section;

FIG. 2 is a sectional elevational view of the propulsor unit taken substantially in the plane of line 22 of FIG. 5;

FIG. 3 is an enlarged front elevational view of the tail pipe;

FIG. 4 is a greatly enlarged fragmentary sectional view of the upper portion of the combustion chamber housing and associated parts;

FIG. 5 is a sectional view on line 5-5 of FIG. 2 but on a larger scale;

FIG. 6 is an end elevational view of the propulsor taken along the plane of line 6--6 of FIG. 2, the view being on a larger scale and with a portion of the propulsor broken away;

FIG. 7 is a sectional view on line 7-7 of FIG. 2;

FIG. 8 is a fragmentary sectional view upon line 8-8 of FIG. 5;

FIG. 9 is a fragmentary sectional view on line 9-9 of FIG. 8;

FIG. 10 is an enlarged fragmentary sectional view on line Iii-10 of FIG. 8;

FIG. 11 is a fragmentary sectional view of a single ejector and associated means for defining a flow passage about the ejector and therebeyond, the view being substantially along line 1111 of FIG. 6 but with the central tube partially broken away;

FIG. 12 is a fragmentary sectional view substantially on line Il2 ;2 of FIG. 6; and

FIG. 13 is an enlarged fragmentary sectional View on line 1313 of FIG. 4.

More particularly describing the invention, referring first to FIG. 1, numeral 11 generally designates the socalled hydrapulse motor which is shown attached by a bracket assembly 12 to the transom l3 outboard of a boat 14. In general, the motor includes a combustion chamber 15, a propulsor or propulsion unit 16 and a tail pipe 17 connecting the two. The gases of combustion resulting from explosions in the combustion chamber '15 pass forcibly down the tail pipe 17 into propulsion chambers located in unit 16, later to be described, these chamhere being open at the rear. The liquid in these chambers is forced out ahead of the explosion gases, thereby propelling the motor and boat by reaction.

Referring now to the combustion chamber construction (see FIGS. 1, 4 and 13), this comprises a casing 20 having a central opening 21 at its lower end communicating directly with the interior of the tail pipe 17 which is fixed to the casing. Mounted in the lower portion of the casing is a spark plug'23 which can be actuated by any conventional electrical means for such purpose. Within the casing I provide an adjustable cylinder head 25 which closely, slidably fits the inner cylindrical surface 26 of the housing. The cylinder head is mounted at the lower cylindrical end portion 27 of a stem 28, being retained by a snap ring 29. The stem is provided with external threads 28 received in an internally threaded hub portion 36 of a spider 31 mounted in the upset end 3 2 of the casing 29. An adjustment wheel :33 is fitted to the cylindricatl upper end portion 34 of the sleeve 28, being held by a set screw 36. By rotating the wheel 33, the head may be moved axially of the casing to adjustably vary the displacement of the combustion chamber 38.

The cylinder head 25 is provided with a series of arcuate air inlet openings 49 between concentric circular ribs 41 and radial ribs 42. These openings are controlled by a disk air-inlet valve 44- which is carried beneath the cylinder head upon a sleeve 45 mounted within member 28. The valve is supported by a valve-support spider 46 mounted on the lower end of the sleeve and retained by a fuel nozzle 48 which threads into the lower end of the sleeve. The nozzle also serves to retain a valve seat 50 in a counterbore 51 of the sleeve. The valve plate freely receives the cylindrical portion 52 of sleeve 45 and normally rests upon the upper surfaces of spider as in spaced relation below the under-surface of the cylinder head in which position air is free to enter the combustion chamber through openings 40. To facilitate passage of air, the valve plate is perforated with holes 54 positioned out of registration with the holes 46 of the cylinder head so that when the valve plate is forced upward against the cylinder head during each explosion cycle, it will serve to close openings 40 therein.

Within sleeve 45 I provide a needle valve 56 which seats against valve seat Ed. The valve is threadedly mounted for adjusted positioning within a cap 58 threaded onto the upper end of sleeve 45. The cap retains a fuel inlet swivel fitting 69 having a fluid passage '61 and internal groove 6-2 in communication with the interior of the sleeve 45 through ports 63 therein. Suitable seal rings 64 are disposed to sealingly engage the fitting while seal rings 65 on an enlargement 66 of the valve sealingly engage the inside of the sleeve.

Just below fitting 6t} 1 provide a knob 7 (l on the sleeve which is secured by a set screw 71. This knob provides a means for readily rotating sleeve 45 within member 28 to effect vertical adjustment of the valve disk 4 to vary the clearance of the valve disk relative to the cylinder head.

Any suitable means can be provided for furnishing fuel under pressure to the fitting 60 which I have shown connected by a fuel conduit 73 to a fuel supply tank '74 in FIG. 1. The nozzle 48 would be of the atomizing type for liquid fuels and of the orifice type for gaseous fuels.

Referring now to the propulsion unit 16, this is formed to provide a multiplicity of axially disposed ejectors 8i) defining propulsion chambers 81, which are in open communication with the combustion chamber 38 at their forward ends through the tail pipe 17 and open to the liquid in which the device is submerged at their other ends. The chambers are formed by Wall means to be described within a casing 82 having a central cylindrical section 33 and an inwardly curved rear section 34 which terminates in an opening 85. The casing also has a forward or inlet section comprising a double-walled annular assembly 86 defining an inlet opening 87 formed thereby. The walls of the inlet portion of the casing are spaced apart throughout most of their axial length, as best shown in FIG. 2, and provide a gradually enlarging inlet chamber 88.

Within the housing I provide a gas distributor spider 90 which has a cylindrical central portion 91 from which multiple hollow sections 92 extend radially. The central section includes a forwardly projecting tubular section 93 upon which an inlet fairing 94 is mounted. The other end of the central section is mounted within the forward end of a tube 95 extending along the longitudinal axis of the casing 82. Internally, the spider is formed to provide a central rearwardly projecting internal wall means shaped to provide a passage 98 through the central portion of the spider to the interior channel 99 of each of the hollow sections 92.

Each of the ejectors 80 projects rearwardly from one of the radial sections 92 of the gas distributor spider 90 as will be described. In order to conduct the explosion gases from the combustion chamber to the spider 9t and thence to the propulsion chmbers 81, the tail pipe is so mounted as to be in communication with the rear central portion of the spider 9d. The tail pipe includes an upper cylindrical section 190, a central downwardly and rearwardly diverging laterally contracting section 101 and 1. a lower section 162. The latter is mounted through the housing 32 and terminates at its lower end in communication with the interior conical area 103 of the tube 96, being open thereto through hole 104 in the tube. A partition wall 165 is disposed comically beneath opening 194 to effectively isolate a dead end chamber 106 in tube 96 so that the gases of combustion will pass directly from the tail pipe into the spider o.

The radial sections 92 of the spider are U-shaped in cross section and each comprises a pair of laterally spaced walls 119 of similar configuration connected by a forwardly facing inclined wall section 111, the walls and wall section providing the rearwardly opening channel 99 for the passage of gases into the propulsion chamber.

Each propulsion chamber is defined in part by one of the aforementioned radial sections 92 of spider 99 and by a wall means designated generally 113 and comprising the side walls 114 and inner edge wall 115 connecting the same. Each of the side walls has a laterally projecting and laterally curved flange 116 by means of which the assembly is attached to the inner wall of the casing section 83. Thus the latter forms the outer edge wall of the chamber opposite wall 115.

The walls 114- of each chamber 81 are attached at their forward margins to the marginal portions 100' of a. radial section 92 of the spider and from there they extend rearwardly, divergingly through relatively straight sided sections 114 to their region 113 of greatest divergence from which they taper inwardly to terminate in an opening 119. Each of the walls 114 is provided with an over-all pattern of perforations 129 which extend from the spider section 92 nearly to the area 118. These perforations are normally covered by valves 121 of a resilient nature and accordingly may be formed of rubber or synthetic rubber. Each valve may comprise a strip of material covering several of the openings and bonded or otherwise attached to the interior surface of the wall along its forward margins only. i

I provide a louvered reinforcing plate 124 on each wall 1-14 overlying the perforate areas. These can be attached at 125 and 126 by rivets, or they can be spot welded at intervals. The plates provide slots 12% over the openings 12G in the walls 114 for inlet of liquid.

What I will term the primary flow through the pro pulsion unit is the flow of exhaust gases and liquid moved thereby rcarwardly through the propulsion chambers on each explosion cycle. I also have means within the propulsion unit for providing what I will term a secondary flow of liquid. This takes place in the space exterior of the propulsion chambers but within the casing of the propulsion unit as best seen in FIGS. 11 and 12. Thus, liquid may enter the forward end of the propulsion unit through opening 87 and then pass between the propulsion chamber walls 114 and emerge through the rear opening 85 of the unit. Some of the liquid constituting the secondary flow is utilized at each cycle of the motor for refilling the propulsion chambers at the completion of the explosion cycle, and one of the features of the invention is the provision of means within the propulsion unit casing to direct and control the secondary flow to best utilize it for this purpose. I accomplish this by providing what 1 term venturi-forming bodies 139 which extend generally axially and radially of the interior of the propulsion unit casing, with each body being disposed between two of the propulsion chambers or ejectors and bisecting the angle formed thereby. Each body 130 has been shown as solid for the sole purpose of simplifying the drawing, however in practice these bodies might be hollow and made of sheet metal. Each body has an outer surface 131 which fits against and conforms to the inner surfaces of sections 83 and 84 of the casing 82. The surface 131 has no significance since it would be unnecessary if the bodies 130 were hollow. Each body is generally triangular in cross section on a plane normal to the longitudinal axis of the propulsion unit casing, having two oppositely identical sides 132 which converge in a direction inwardly of the casing 32 toward the center thereof. The inner margins of the two sides 132 meet to form an inner ridge or apex which includes a forward section 133- and a rear section 134 disposed to form an obtuse angle. Intermediate the ridge sections 133 and 134, is a flattened somewhat concave section 135 which fits against the central tube 96. The two sides 132 not only converge radially inwardly from the casing 82, but also converge toward the front and toward the rear, from a nearly centrally located convexly curved intermediate section 132A, each side having a forward section 1628 and a rear section 132C.

The bodies 130 are disposed to extend from the rear edge of the propulsion unit casing 82 forwardly to a region about midway of the length of the ejectors, and thus a venturi-like passage is provided between each pair of bodies 130 consisting of a converging upstream section 140, a throat section 141, and a diverging downstream section 142. The ejectors extend through the converging section and into the entrance area of the throat 141. What I have termed the primary flow thus takes place through the propulsion chambers 81 and the secondary flow through the venturi-like spaces external thereto as best shown in FIG. 12.

With the construction described I avoid rapid accelerations and decelerations of the liquid in the filling oi the propulsion chambers during the intake portion of the cycle. Thus, when the valves close during the explosion portion of the cycle the secondary flow is free to continue downstream through the venturi-like passages thereby avoiding rapid deceleration of thisflow. When the intake valves open, the secondary flow, being already in rapid motion, does not have to be rapidly accelerated to fill the propulsion chambers.

Still further advantages are: that liquid ejected from the propulsion chambers through the venturi throat during the explosion portion of the cycle serves to draw additional water from the secondary flow through the venturi throat thereby keeping the secondary flow in rapid motion preparatory to the filling motion of the cycle and augmenting the total mass flow through the propulsion unit thereby increasing the total thrust.

The ejectors being flared outwardly toward the downstream end have three novel advantages, namely, the liquid in flowing into the propulsion chambers need turn at a lesser angle in flowing from the secondary flow to the primary; being narrower at their upstream end where the secondary flow is slower and wider at the downstream end where the secondary flow is faster, the ejectors tend to fill at a uniform rate along their length; and fiinally being wider at the downstream end, the ejectors are better able to jettison the entrapped exhaust gases.

The forward section of housing 82 is so shaped as to provide a restricted opening at the intake such that liquid entering at ambient pressure is slowed down by the diverging shape of the fairing downstream from the intake. This, by well known principles of fluid flow, raises the pressure of the liquid making up the secondary flow and thereby increases the pressure diflerential between the secondary and primary flows so that the water flows more rapidly from the secondary to the primary when the ejector valves open for the intake portion of the cycle.

A constant, although fluctuating, low pressure area is maintained in the throat of the venturi. This is caused for a portion of the cycle by the effect of the discharge of the primary flow through the venturi, and for the remainder of the cycle by the inertia-generated flow of the secondary flow discharging through the venturi. In eflect, during the time that liquid is entering the ejectors through the valves, the secondary flow at the venturi becomes the primary flow, pumping the residual gases from the ejectors and simultaneously lowering the pressure in the ejectors, which still further increases the pressure differential in the ejectors, which still further increases the differen- 6 tial pressure across the water inlet valves and therefore adds again to the speed of filling the ejectors. This whole effect not only aids the filling speed, but also adds greatly to the stability of the ejector function. In this regard, it smooths out the pulsing of the motor, acting, in a sense, like a flywheel.

I claim:

1. In a pulse jet propulsion motor having a combustion chamber, a propulsion unit adapted to be submerged in liquid, such as water, comprising an open-ended casing through which the liquid can move in a given direction, an ejector mounted in said casing extending axially thereof and having wall means defining a propulsion chamber open at its downstream end, said propulsion chamber being characterized by being relatively narrow with aperrtured side walls diverging in a direction downstream, check valve means controlling the apertures in said side walls to permit fiow therethrough into said propulsion chamber, said side walls converging in a region beyond the apertured area thereof, conduit means establishing open communication between the upstream end of said propulsion chamber and said combustion chamber, means mounted in said casing oircumferentially spaced from said ejector and extending axially of the casing downstream of the downstream end of said ejector and cooperating with the casing to define a flow passage through the casing characterized by an upstream section about said ejector converging downstream to a reduced throat section in the region of the downstream end of said ejector and a diverging downstream section .therebeyond, the cross-sectional area of the space between said ejector and the means defining the flow passage through the casing being less at a region a short distance upstream from the downstream end of said ejector than at said downstream end thereof.

2. In a pulse jet propulsion motor having a combustion chamber, a propulsion unit adapted to be submerged in liquid, such as water, comprising an open-ended casing through which the liquid can move, a plurality of ejectors disposed radially in said casing and extending axially thereof and spaced circumferentially of each other, said ejectors providing propulsion chambers open at their downstream ends, a manifold secured at the upstream ends of said ejectors, conduit means establishing open communication between said combustion chamber and said manifold whereby gases of combustion are distributed to the upstream ends of said propulsion chambers through said manifold, said ejectors containing check valve-controlled liquid inlet openings between their ends, and passage-defining means mounted in said casing extending radiially and axially thereof between said ejectors from a region intermediate the ends of said ejectors to a region downstream thereof, said passage-defining means cooperating with the casing to provide flow passages each containing an ejector characterized by an upstream section about the ejector converging downstream to a reduced throat section in the region of the downstream end of said ejector, and a diverging downstream section therebeyond, each ejector having a portion of greatest width adjacent to but spaced upstream from its downstream end and converging from said portion to its open downstream end.

3. In a pulse jet propulsion motor having a combustion chamber, a propulsion unit adapted to be submerged in liquid, such as water, comprising an open-ended casing, a plurality of ejectors mounted in said casing in laterally spaced relation and extending axially thereof, said ejectors being open at their downstream ends for ejection of fluid therethrough, conduit means establishing communication between the upstream ends of said ejectors and said combustion chamber, said ejectors having check valve-controlled inlet openings between their ends, and means with in said casing defining venturi-like passages for flow of fluid therethrough, said ejectors each being individually positioned in one of said venturi-like passages, the crosssectional area of the space between each ejector and the means defining venturi-like passages through the casing being less at a region a short distance upstream from the downstream end of said ejector than atthe downstream References Cited in the file of this patent 915,972 end thereof. 1 049 498 4. In a pulse jet propulsion motor, means forming a 5 1375601 combustion chamber, an open-ended casing adapted to be 1 submerged in a liquid, such as water, a plurality of later- 2,522,945 ally spaced ejectors mounted in said casing and extending 2,523,354 axially thereof, said ejectors being open at their down- 2 644 297 stream ends, a manifold connected to the upstream end 10 2,674,091 of said ejectors, a tail pipe connecting said manifold and 2,696,077 said combustion chamber, said ejectors having check 2,701,950 valve-controlled inlet openings between their ends, and ,3 means in said casing defining a venturi-like passage about 15 3,024,597 each ejector, said ejeotors being characterized by being of gradually increasing cross-sectional area from their up- 502 776 stream ends to a region adjacent but short of their down- 741553 stream ends and being of decreasing cross-sectional area 743,492 therebeyond. 305 1 UNITED STATES PATENTS Lake Mar. 23, Lake Jan. 7, Morize Apr. 19, Neuland Jan. 20, Gongwer et al. Sept. 19, Flanagan Oct. 31, Coxe et a1. July '7, Malick Apr. 6, Goodman Dec. 7, Huber et al. Feb. 15, Schmidt Nov. 18, Beck et al Mar. 13,

FOREIGN PATENTS France Feb. 18, Great Britain Nov. 30, Great Britain J an. 18, Italy Jan. 30, 

2. IN A PULSE JET PROPULSION MOTOR HAVING A COMBUSTION CHAMBER, A PROPULSION UNIT ADAPTED TO BE SUBMERGED IN LIQUID, SUCH AS WATER, COMPRISING AN OPEN-ENDED CASING THROUGH WHICH THE LIQUID CAN MOVE, A PLURALITY OF EJECTORS DISPOSED RADIALLY IN SAID CASING AND EXTENDING AXIALLY THEREOF AND SPACED CIRCUMFERENTIALLY OF EACH OTHER, SAID EJECTORS PROVIDING PROPULSION CHAMBERS OPEN AT THEIR DOWNSTREAM ENDS, A MANIFOLD SECURED AT THE UPSTREAM ENDS OF SAID EJECTROS, CONDUIT MEANS ESTABLISHING OPEN COMMUNICATION BETWEEN SAID COMBUSTION CHAMBER AND SAID MANIFOLD WHEREBY GASES OF COMBUSTION ARE DISTRIBUTED TO THE UPSTREAM ENDS OF SAID PROPULSION CHAMBERS THROUGH SAID MANIFOLD, SAID EJECTORS CONTAINING CHECK VALVE-CONTROLLED LIQUID INLET OPENINGS BETWEEN THEIR ENDS, AND PASSAGE-DEFINING MEANS MOUNTED IN SAID CASING EXTENDING RADIALLY AND AXIALLY THEREOF BETWEEN SAID EJECTORS FROM A REGION INTERMEDIATE THE ENDS OF SAID EJECTORS TO A REGION DOWNSTREAM THEREOF, SAID PASSAGE-DEFINING MEANS COOPERATING WITH THE CASING TO PROVIDE FLOW PASSAGES EACH CONTAINING AN EJECTOR CHARACTERIZED BY AN UPSTREAM SECTION ABOUT THE EJECTOR CONVERGING DOWNSTREAM TO A REDUCED THROAT SECTION IN THE REGION OF THE DOWNSTREAM END OF SAID EJECTOR, AND A DIVERGING DOWNSTREAM SECTION THEREBEYOND, EACH EJECTOR HAVING A PORTION OF GREATEST WIDTH ADJACENT TO BUT SPACED UPSTREAM FROM ITS DOWNSTREAM END AND CONVERGING FROM SAID PORTION TO ITS OPEN DOWNSTREAM END. 